Anchor structure for mines, tunnels and the like



Nov. 27, 1956 A. FISCHER ETAL ANCHOR STRUCTURE FOR MINES, TUNNELS AND THE LIKE 2 Sheets-Sheet 1 Filed Dec. 11, 1952 August LLs'Ae I- e- WL'ZAeZm /)e 22 Zer- Nov. 27, 1956 A. FISCHER EI'AL ANCHOR STRUCTURE FOR MINES, TUNNELS AND THE LIKE 2 Sheets-Sheet 2 Filed Dec. 11, 1952 Aug WLZLeZ-m Keizzel- ANCHOR STRUCTURE FUR MINES, TUNNELS AND THE LIKE August Fischer, Dortmund-Gartenstadt, and Wilhelm Ketzler, Unna, Westphalia, Germany Application December 11, 1952, Serial No. 325,426 Claims priority, application Germany May 5, 1952 4 Claims. (Cl. 61-45) This invention relates to an anchor structure for mines, tunnels and the like, and the tools for producing bore holes for the anchors.

It is an object of this invention to provide a bore hole for the anchor for mine ceilings by providing an enlarged chamber in the end of the bore hole and such chamber has a short depth and is provided with an internal surface against which the anchor contacts. It is a further object of the invention to provide various internal configurations for the enlarged end chamber together with surfaces against which the anchor will abut.

Another object of the invention resides therein that the anchor is made in two parts by dividing it axially so that the end of each part is provided with an enlarged head of such siz that the two parts when side by side may be inserted into the bore hole and when adjusted edge to edge the two parts will contact the enlarged chamber by means of the two heads. In this position the heads of the two parts will contact the circular shoulder in the enlarged chamber of the bore hole. A still further object of the invention resides in the provision of a lock mechanism for the two parts of the anchor to hold them in position and lock th parts in operative position together with means to hold the shanks of the anchor parts in separated positions.

In all of the modifications of the invention ther is the advantage that irrespective of the character of the tunnel or mine and the specific composition of the rock formation, a positive connection of the anchors is attained without the necessity of boring a specific diameter of hole or that all the holes shall have the same exact diameter. This is particularly true since the pressure connection between the end of the anchor to the rock is not as heretofore dependent on the amount of friction around the circumference of the bor hole but since the hold in the rock is due to an axial force on the shoulder in the enlarged chamber of the bore hole a positive and permanent securing of the anchor is attained. The diameter of the chamber-like enlargement of th bore hole at the end thereof is chosen within certain limits depending upon the character of the rock, the roof of which is to be supported.

Further objects will be apparent from the following description when considered in connection with the accompanying drawings, in which:

Figure 1 is a diagrammatic view showing in elevation the anchors as applied to the ceiling of a subterranean passage,

Fig. 2 is a longitudinal section of a bore hole,

Fig. 3 is a longitudinal section of the bore hole showing the tool in operating position to cut the enlarged chamber in the end thereof,

Figs. 4 and 5 are longitudinal sections of the bore hole showing details of the tool,

Fig. 6 is a longitudinal section of the bore hole showing the tool in operative position,

Fig. 7 is a longitudinal section of the bore hole showing a modified tool in cutting position,

rates Patent 0 2,771,746 Patented Nov. 27, 1956 Figs. 8 and 9 are longitudinal sections of the bore hole showing a divided tool in two different positions.

Fig. 10 is a longitudinal section of a part of the bore hole showing a detail of the tool, 4

Fig. 11 is a cross section of the tool taken on line 11-l1 of Fig. 10,

Fig. 12 is a longitudinal section of the bore hole show* ing a modified tool.

As clearly shown in Fig. 1, the ceiling of a mine chamber passage or other part or tunnel is spanned by a plurality of anchors 1. These anchors are directed upwardly as shown in vertical directions, but of course they may be directed at an angle if desired. The number of such anchors is of course dependent upon the various circumstances and characteristics of the mine and rock. In addition to the anchors various beams and other elements may be used cooperating with the anchors as shown in Fig. 1.

In order to provide for a good security for each anchor, a bore hole 2, Fig. 2, is provided at its inner end with an enlarged chamber 3 which as to its depth need not essentially exceed the diameter of the bore hole and as a matter of fact can be made as short as possible. Normally a length of approximately 10 to 15 cm. would b sufficient. The enlarged chamber 3 is so formed that a shoulder portion 4 is provided between the bore hole 2 and the chamber 3.

As shown in Fig. 3 one can use a borer 5 to enlarge the end of the bore hole 2 into an enlarged chamber. The borer 5 is provided with a boring crown or head which is in the form of an eccentric cutter 6. In accordance with the forms of the invention of Figs. 4 to 6, the boring head of the tool may be provided with a crown 7 into which a scissor-like cutter 8 is provided having cutting elements which swing outwardly, so that the scissor-like elements are mounted in the crown 7 by means of a pin or bolt 9 guided in slots 10. The degree of swing of the scissorlike elements or cutters is limited by the abutment surfaces 11 in the crown 7. In Fig. 4 there is illustrated the position of the parts during the insertion of the tool in the bore hole with the cutter elements in the non-cutting positions. This is the same position of the partswhen the tool of Figs. 4 and 5 is removed from the bore hole. As shown in Fig. 5 both cutters are povided with laterally projecting abutment surfaces 12 which in the cutting positions of the cutters, that is in the swung-out positions, will abut against the outer and upper portions of the crown of th boring tool. Fig. 6 shows the tool in the cutting position and it is clearly discernable, that by the scissor formation of the outwardly swung cutters 8, an enlarged chamber will be cut into the end of the bore hole of the desired length. In addition to the tool shown in the drawings other forms of such tools may be used to form the enlarged end chamber in th bore hole and it is essential in this connection that the tool shall have cutting members which will swing outwardly or which slide laterally relative to the longitudinal axis of the tool.

The anchors which are to be provided and secured in the bore holes having enlarged end chambers, may be designed in many different modified forms. Fig. 7 illustrates a form of anchor in which near the front end of the shaft 1, a pair of abutment levers or arms 14 are pivotally mounted on a shaft 13 which are adapted to swing outwardly in a lateral direction similar to an umbrella. Between the arms 14 a spring 15 is provided which urges the arms outwardly relative to each other. Upon insertion of the anchor into the bore hole and as soon as the end 3 thereof is reached the spring 15 will force the arms 14 outwardly in the locking position in which. the ends of the arms will contact the shoulder surfaces 4 of the enlarged chamber. In this form of anchor the chamber 3 may be provided a short distance from the end of the bore hole so that the head 16 of the anchor shaft may be located in the actual end of the bore and which has a diameter equal to the diameter of the bore hole. The anchor 1 may be secured in the bore hole with tension by means of a nut screwed on the outer end of the anchor shaft, as shown in Fig. l. The anchors may be provided with round or quadrilateral plates in order to tension the anchors to the roof of the mine shaft or tunnel.

Figs. 8 to 11 illustrate a form of anchor made in two parts 1a and 1b. The total diameter of both shafts 1a and 1b is smaller than the diameter of the bore hole 2. Each shaft 1a and 1b is provided with an enlarged head 17 and each head has a diameter or cross sectional area so that when one shaft 1a is inserted into the bore hole, the other shaft 1b may be inserted and the enlarged head 17 will move past the head of the other shaft as shown in Fig. 8. In the end position of the shafts 1a and 1b the heads 17 will be adjacent each other by surface contact 17a and the shoulders 18 of each head will engage and bear on the shoulder 4 of the enlarged chamber 3. As shown in Fig. 9 in the secured position of the anchor, a space is formed between the shafts 1a and 1b, and between this space the carrying and tension elements are provided. The parts of the shafts which project from the bore hole 2 are provided on the outer surface with channels or gutters 19 which serve to receive and secure the lock member 20. The lock member 20 is in the form of a frame to receive the cam member 21. As shown in Fig. 11 each shaft 1a and 111 will be forced against the lock frame by the cam 21 whereby the two shafts 1a and 1b will be locked in their respective positions. On the upper side of the lock member 20 which is a slanting surface 22, there is guided a high edged cam member 23 which serves to tension the anchor in an axial direction. In the form illustrated the cam 23 abuts on its upper side against a plate 24 which is adjacent the roof of the tunnel or mine shaft.

Upon driving in of the cam 23 the anchor is placed under tension. The cam can also serve the purpose of directly or indirectly supporting the suspended members between it and the locking member.

Fig. 12 shows a form of the anchor which is similar to the anchor of Figs. 8 to 11. In this case, however, the heads of the anchor shafts 1a and 1b are formed so that one can tell them apart. Since in many cases the anchors are never removed once they are set in place, the two parts of the anchor may be joined by Welding at the heads thereof or they may be joined by means of an artificial resin so that for all practical purposes a unitary anchor is produced.

In accordance with this invention it is possible to produce a positive anchorage by the use of a cement material or a similar substance which will harden after being applied. This cement is applied after the anchor is placed in position and it can be applied by a pressure pump or other means. As Fig. 12, shows, after the cement is forced into place a change in position of the anchor is not possible so that a secure fastening is made for the anchor. The application of the cement is carried out in such a way that the anchor cannot be salvaged since in most cases the anchors have served their purpose by supporting the roof for a great many years. The invention is of course not limited to actual mine shafts and passages since the anchors may be used in and installed where it is desired to support the roof structure irrespective of its actual composition. Also the anchors may be used to form suspension means for various elements such as electric wires and cables, pipes and the like as well as for all other types of suspension.

'It is pointed out that the anchor according to the invention as well as the manner of securing the same may be used in combination with wire ropes both as suspension means and for other purposes. It is also possible to use the invention in various combinations and it is equally adaptable to be utilized as suspension means for pipes, wires, cables, and other elements and devices as well as to utilize the anchors to support mine roofs, sides and tunnels of all types.

We claim as our invention:

1. A supporting means for the roofs of mines having therein bore holes each having an enlarged chamber in the inner end thereof and a shoulder portion intermediate and between the enlarged chamber and the hole, comprising an elongated anchor in two longitudinal parts movable relative to each other and provided in the bore hole and chamber and each part having at its inner end a laterally extending and enlarged head which heads cooperate with each other to contact the shoulder portion in the bore hole to securely hold the anchor in the hole, said anchor parts both being completely secured in the bore hole in spaced relationship to each other and contacting each other at the enlarged head portions, and means extending between the two remaining parts maintaining them in spaced relationship.

2. A supporting means for the roofs of mines having therein bore holes each having an enlarged chamber in the inner end thereof and a shoulder portion intermediate and between the enlarged chamber and the hole, comprising an elongated anchor in two longitudinal parts movable relative to each other and provided in the bore hole and chamber and each part having at its inner end a laterally extending and enlarged head which heads cooperate with each other to contact the shoulder portion in the bore hole to securely hold the anchor in the hole, said anchor parts contacting each other at the enlarged head portions and the remaining parts of the anchor being spaced from each other when the two anchor parts are both in the bore hole, and a lock member and 'a pair of wedge members secured on the protruding ends of the anchor to maintain the two parts of the anchor spaced from each other.

3. A supporting means for the roofs of mines having therein bore holes each having an enlarged chamber in the inner end thereof and a shoulder portion intermediate and between the enlarged chamber and the hole, comprising an elongated anchor in two longitudinal parts movable relative to each other and provided in the bore hole and chamber and each part having at its inner end a laterally extending and enlarged head which heads cooperate with each other to contact the shoulder portion in the bore hole to securely hold the anchor in the hole, the two parts of the anchor being provided with semicircumferential channels on the ends opposite the enlarged heads, and a lock member on the outer ends of the anchor parts which is in the form of a frame having parts contacting into the channels to secure the two parts of the anchor in separated and spaced relationship.

4. A supporting means for the roofs of mines having therein bore holes each having an enlarged chamber in the inner end thereof and a shoulder portion intermediate and between the enlarged chamber and the hole, comprising an elongated anchor in two longitudinal parts movable relative to each other and provided in the bore hole and chamber and each part having at its inner end a laterally extending and enlarged head which heads cooperate with each other to contact the shoulder portion in the bore hole to securely hold the anchor in the hole, a lock member on the parts of the anchor which protrude from the bore hole to maintain the two parts of the anchor in separated and spaced positions, and a cam member projecting between the two parts of the anchor and wedging against the lock member and the roof of the mine.

(References on following page) UNITED STATES PATENTS Preslar Dec. 15, 1903 Kohler Sept. 22, 1914 Gay Nov. 21, 1916 Roney May 8, 1923 Bonham Oct. 4, 1938 White Aug. 15, 1944 6 Beijl Apr. 9, 1946 Crockett Sept. 1, 1953 FOREIGN PATENTS Austria Nov. 10, 1904 OTHER REFERENCES Eng. & Mining Journal, pages '7072, May 1943 issue. 

